The present invention relates to a MAC protocol in a wireless body area network capable of processing emergency data and a wireless network communication method using the same, and more particularly, to a MAC protocol in a wireless body area network capable of processing emergency data and wireless network communication method using the same, which can efficiently process emergency data and guarantee low delay and high reliability of the emergency data by substituting a Contention Free Period (CFP) of the WBAN MAC protocol with a Mixed Period (MP) for processing the emergency data, and setting an inactive period as an Extended Period (EP) for reallocating a Guaranteed Time Slot (GTS) which is not additionally allocated and guaranteed due to processing of the emergency data.
The present invention relates to a MAC protocol in a wireless body area network capable of processing emergency data and a wireless network communication method using the same, which can process, in a body area within 3 m, emergency data appropriate for applications having different medical/non-medical characteristics and objects and a WBAN network system in which periodic or aperiodic characteristics of the applications are used together.
Following WLAN and WPAN techniques, the Wireless Body Area Network (WBAN) is spotlighted recently as a wireless technique for medical/non-medical communication in a body area.
The WBAN is a network capable of performing wireless communication within a body area. Here, the body area wireless communication refers to wireless communication in which terminals positioned inside or outside of a human body communicate with other devices placed within about 3 m.
The most outstanding characteristic of WBAN, distinguishing WBAN from other networks such as WLAN, WPAN and the like, is considering a medical device as a Killer item. Another outstanding characteristic of the WBAN is considering wireless communication of a human body transplanting type wireless device transplanted inside a human body.
Accordingly, WBAN is currently applied to a variety of uses and may be broadly divided into medical and non-medical wireless devices. That is, WBAN may be divided into a non-medical wireless device for communications between consumer electronics, a human body transplant type wireless device transplanted inside a human body to monitor a health state inside the human body or to handle a situation wherein an abnormal state occurs inside the human body, and an external wireless device for transmitting and receiving data to and from medical sensors placed within 3 m from the human body. A MAC protocol of such a WBAN should simultaneously satisfy characteristics of medical devices and consumer electronics.
The IEEE 802.15.4 ZigBee MAC protocol, which is a representative MAC protocol of WBAN, coordinates medium access of a device using a hybrid superframe structure which uses a beacon.
A superframe is divided into an active period for exchanging data between devices and an inactive period in which a device may operate in a sleep mode.
The active period is again divided into a Contention Access Period (CAP) where medium access is allowed through contention among devices and a Contention Free Period (CFP) where only selected devices may exchange data at a predetermined time point.
The ZigBee MAC protocol aiming at low power consumption and low transmission rate divides a period into 16 equal slots and is configured of a Contention Access Period (CAP) and a Contention Free Period (CFP), and the CFP configured of 7 Guaranteed Time Slots (GTSs) is in charge of guaranteed transmission.
Conventional ZigBee provides GTS allocation limited to 7. In the GTS period, resources are allocated in advance only to specific pre-selected devices, and thus devices other than the corresponding specific devices cannot transmit data. Accordingly, when 8 or more nodes request the GTS, the GTS may not be allocated to nodes excluding seven nodes.
Various methods for improving limitations in allocating GTS are invented in order to overcome the drawbacks of conventional ZigBee as described above, and have a common feature in that continuous allocation of GTS is dynamically or statically performed. In this case, the CFP grows to be large. In consideration of the characteristics of WBAN which provides medical services, reliably and rapidly processing emergency data is one very important requirement, and if the reserved CFP increases, delay time of the emergency data is extended.